Specific leaf area in a coastal temperate deciduous forest: species and salinity effects
Lillie Haddock
8/13/2019
Motivation
Specific leaf area (SLA, the ratio of leaf area to leaf dry mass) is an important trait for plant physiological, structural, and modeling analyses. SLA is also a useful measurement to upscale plant production, vegetation community composition, and other processes in Earth System Models, providing current-day benchmarks and improving predictions of future vegetation structure and function in terrestrial ecosystems.
We investigate SLA differences between plots of varying elevation and salinity exposure along a tributary of the Chesapeake Bay. The goals of this project are to (i) quantify SLA of eight major tree species, at multiple canopy heights, in temperate deciduous forests at the Smithsonian Environmental Research Center (Maryland, USA); and (ii) test for effects of soil moisture and saltwater exposure on SLA by comparing samples taken at shoreline and upland positions, with the shoreline samples taken along a ~2 km tidal creek that provided a natural salinity gradient.
Map of SERC with plots labeled:
Sampling Design
I think this would be a good place for methods
Figure 1: Collecting samples using a pole pruner
Figure 2: Collecting samples using a hand pruner
Figure 3: All the samples after a morning of collecting
(I will evenually figure out how to only show the four species we are sampling from :) )
| Species | Species Common | Number of Trees Sampled | Average Diameter (cm) |
|---|---|---|---|
| Acer rubrum | Red maple | 26 | 21.30 |
| Carya glabra. | Pignut hickory | 6 | 20.28 |
| Cornus florida. | Flowering dogwood | 2 | 3.20 |
| Fagus grandifolia | American beech | 30 | 13.93 |
| Liquidambar styraciflua | Sweet gum | 28 | 19.74 |
| Liriodendron tulipifera | Tulip poplar | 14 | 37.11 |
| Nyssa sylvatica | Black gum | 23 | 12.50 |
| Quercus alba | White oak | 19 | 17.31 |
SLA Calculation
SLA is calculated using the ratio between a leaf’s one-sided fresh leaf area and its total dry mass.
sla <- sla %>%
mutate(specific_leaf_area = round(Leaf_Area_cm2 / Leaf_Mass_g, 3)) ## Date Tag No_Tag_Plot
## Length:148 Length:148 Length:148
## Class :character Class :character Class :character
## Mode :character Mode :character Mode :character
##
##
##
##
## No_Tag_Species_code No_Tag_DBH Position n_Leaves
## Length:148 Min. : 1.10 Length:148 Min. :4.000
## Class :character 1st Qu.: 8.00 Class :character 1st Qu.:6.000
## Mode :character Median :13.00 Mode :character Median :6.000
## Mean :15.31 Mean :5.831
## 3rd Qu.:21.10 3rd Qu.:6.000
## Max. :49.60 Max. :9.000
## NA's :111
## Leaf_Area_cm2 Leaf_Mass_g Notes specific_leaf_area
## Min. : 5.23 Min. :0.1810 Length:148 Min. : 25.51
## 1st Qu.:156.70 1st Qu.:0.6435 Class :character 1st Qu.:180.99
## Median :243.89 Median :0.9390 Mode :character Median :241.74
## Mean :271.84 Mean :1.2074 Mean :241.19
## 3rd Qu.:357.00 3rd Qu.:1.6455 3rd Qu.:295.35
## Max. :914.19 Max. :4.0270 Max. :563.18
## ## Plot Species_code Tag DBH
## Length:471 Length:471 Length:471 Min. : 1.80
## Class :character Class :character Class :character 1st Qu.: 8.85
## Mode :character Mode :character Mode :character Median :18.20
## Mean :22.69
## 3rd Qu.:34.15
## Max. :79.00## Warning: We have blank species codes!Average Specific Leaf Area
## Warning: Removed 3 rows containing missing values (geom_text_repel).
Specific Leaf Area by Species
Hmmm…. not sure where the top left species code went :/
The Relationship Between Specific Leaf Area and Tree Diameter at Breast Height
